1. Field of the Invention
The present invention relates to by-pass oil refining devices for internal combustion engines. By-pass oil refining devices are coupled to the crankcase of an internal combustion engine in an alternative path of lubricating oil flow in automotive vehicles and other machines employing internal combustion engines. Such oil refiners percolate oil through a porous filter material and heat the oil to vaporize and remove volatile contaminants, such as water and fuel.
2. Description of the Prior Art
Contaminated lubricating oil used in internal combustion engines and other equipment is a principal cause of excessive wear and deterioration of engine parts and related equipment. At present, most internal combustion engines presently employ only a conventional mechanical filter for extracting materials such as dirt, carbon, soot, metal particles, and other similar foreign matter from lubricating oil. Liquid contaminants such as condensates, water and fuel, are often emulsified in the lubricating oil and cannot be separated by a conventional filter. It is therefore necessary for the lubricating oil of internal combustion engines using such conventional filters to be changed at regular intervals in order to minimize engine damage by contaminants entrained therein.
In recent years the increasing worldwide price of petroleum products has made it imperative for refining systems to be developed which will recondition lubricating oil so that it may be used and reused indefinately. In this way only small amounts of additional lubricating oil are required by engine usage.
The problem of liquid contaminants has been recognized, and some efforts have been made to develop devices which use heat as a mechanism for separating oil and contaminants. Exemplary prior art devices of this type include Schwalge, U.S. Pat. Nos. 2,635,759; 2,785,109 and 2,839,196; Barrown, U.S. Pat. No. 3,550,781; Priest, U.S. Pat. Nos. 3,616,885; and 4,006,084; and Forsland, U.S. Pat. No. 4,146,475.
These prior art devices have a number of features in common. All involve the percolation of contaminated engine oil through a porous filter, such as cotton or felt padding to remove solid contaminants from lubricating oil. The oil is then forced upwardly through one or several vertical ducts or tubes to a heated vaporization chamber, which is maintained at a pressure reduced from the pressure in the ducts or conduits. When oil emanates from the ducts into this vaporization chamber, the reduced pressure and the heat externally applied to the vaporization chamber by a heating element vaporize the more volatile contaminants, such as fuel and water. The lubricating oil then flows from a vaporization plate to an outlet for recirculation to the lubricating oil pumping system.
Certain problems have existed in all prior by-pass oil refining devices. All conventional oil refining devices are designed to separate both solid and volatile contaminants from lubricating oil. All prior devices apply heat to a vaporization chamber in order to vaporize the volitile contaminants and separate them from the lubricating oil. However, the systems devised for this purpose are inadequate to satisfactorily achieve this separation through vaporization. In conventional systems oil is directed upwardly through ducts in a vaporization plate to a vaporization chamber. In some by-pass oil refining devices the oil is forced under pressure upwardly through a central duct and discharged to strike a concave dome of the oil refiner roof within which a heating element is disposed. In the prior art devices the oil then cascades in rivulets and sheets down the tiers of a vaporization plate while being heated from above by an electrical resistence heater. However, conventional arrangements for discharge of oil into a vaporization chamber do not effectuate adequate removal of vaporizable contaminants. The oil in the jet streams or rivulets in prior art devices is not thin enough to allow heat applied thereto to vaporize volatile components to a satisfactory extent.
Another deficiency of prior art by-pass oil refining devices is that the filter element for filtering solid contaminants from the oil can be removed and replaced only with considerable difficulty. In one type of device, such as that described in U.S. Pat. No. 4,006,084, the casing must be constructed with interiorly directed lugs. A vaporization plate is equipped with notches corresponding to the spacing of the lugs so that the vaporization plate can be forced downward and twisted so that the vaporization clears the lugs at the notches when the vaporization plate is inserted into the case, but the periphery of the vaporization plate between the radial notches is entraped beneath the lugs. A center bolt, captured by the vaporization plate, protrudes upwards and is used to secure a lid to the by-pass refiner through the use of a wing nut.
U.S. Pat. No. 4,146,475, on the other hand, employs a plurality of bolts which the casing is tapped to receive. The bolts extend into the casing and hold the casing together. Numerous other inter-engaging arrangements are employed by means of which the several parts of the by-pass oil refiner can be separated and the porous filter removed and replaced.
All conventional releasable fastening mechanisms are unsatisfactory for a variety of reasons. The system of U.S. Pat. No. 4,006,084 requires considerable compressive and torsional forces on a vaporization plate which is always extremely slippery with lubricating oil when the porous filtering material is to be replaced. Furthermore, the notches in the vaporization plate provide paths of low resistance through the porous filtering material. Oil under pressure in the by-pass oil refiner tends to form "channels" through the porous filtering material directed toward the nut cutout notches in the vaporization plate. This severely reduces the efficiency of contaminant removal by the porous filtering material. Furthermore, fibers from the porous filter are introduced into the decontaminated oil as that oil is passed back to the engine crankcase. In addition, the porous filter compacts with vibration of the engine with which it is used so that the vaporization plate and lid attached thereto can twist and come loose.
Another disadvantage of some of the prior art devices is that oil is introduced through the bottom of the by-pass oil refiner. As a result, oil tends to drain back through the porous filter material back into the inlet when the engine is idle, and thereby dislodge the entrapped contaminants from the lower portions of the porous filtering material and carry these contaminants back to the engine crankcase. This significantly increases the concentration of contaminants in the oil in the crankcase.
In other devices, such as that described in U.S. Pat. No. 4,146,475, oil is introduced laterally and flows downwardly to beneath the porous filtering material. The vaporization plate necessary to allow such flow required extensive machining, including a double boring operation which involves drilling intersecting bores at right angles to each other through the cast vaporization plate in order to achieve a passageway by means of which oil can be introduced into the bottom of the refiner unit.
A further disadvantageous feature of prior art devices is that all conventional devices employ an open vent. Because of vibration and movement of the automotive vehicle, oil frequently escapes from the oil refiner through the vent. Furthermore, because of the open vent and the conventional arrangement of fastening the component parts of the oil refiner together, all conventional oil refiners must be operated in a vertical position.